Database Concepts and Systems PDF

# Basic Concepts - In computing, **data** is translating information into an efficient form as known facts to be processed, recorded, and stored by a computer system. - This information may have the form of text documents, images, audio, or other data types. - In other words, information is data t...

# Basic Concepts - In computing, **data** is translating information into an efficient form as known facts to be processed, recorded, and stored by a computer system. - This information may have the form of text documents, images, audio, or other data types. - In other words, information is data that has been processed into an implicit meaningful form, e.g., Student Information. **Diagram:** The diagram shows a flow of data to information: - **Input**: Data is entered into a system. - **Processing**: Data is processed through the system. - **Storage**: Processed data is stored in a database. - **Output**: Information is outputted by the system. **Users** are depicted interacting with the system both at the input stage and receiving information as output. # Introduction to Database Systems - The database is a kind of repository for collecting computerized data files and allow users to perform a variety of operations, such as: - adding new files to the database - inserting data into existing files - retrieving data from existing files - changing data in existing files - deleting data in existing files - removing existing files from the database # Application Areas of DBMS - **Airlines:** For reservations and schedule information. - **Banking:** For customer information, accounts loans and banking transactions. - **Universities:** For student information, course registrations and grades. - **Credit card transactions:** For purchases on credit cards and generation of monthly statements. - **Telecommunications:** For keeping records of calls, generating monthly bills, maintaining balances on prepaid calling cards and storing information about the communication networks. - **Sales:** For customer, product and purchase information. - **Manufacturing:** For management of supply chain and for tracking production of items in factories, inventories of items in warehouses/stores and orders fo items. - **Human Resources:** For information about employees, salaries, payroll taxes and benefits and for generation of paychecks. - **Web based services:** For taking web users feedback, responses, resource sharing, etc. # Examples of DBMS - **MySQL Database:** It was founded in the year 1995. MySQL was acquired by Sun Microsystems in 2008, then by Oracle after two years. MySQL is one of the largest open-source companies in the world and is popular due to its high level of efficiency, reliability and cost. - **MS-Access:** It was developed by Microsoft and this computer-based application is used to form as well as create the databases on the desktop of computers. It can be used for personal work and for small scale business that required a database. - **Oracle database:** It is the fourth relational database management system which is developed by Oracle Corporation. Oracle database is useful for storing a large amount of data, especially by large organizations. - **Microsoft SQL Server:** It is an RDBMS from Microsoft company which creates computer databases for MS-Windows. Based on customer's requirements, Microsoft has developed various versions of SQL Server. # DBMS Functionality - **Define**: a database in terms of data types, structures, and constraints. - **Construct or Load**: a database on a secondary storage medium. - **Manipulate**: the database querying, generating reports, insertions, deletions, and modifications to its content. - **Concurrent Processing and Sharing**: by a set of users and programs while keeping the data's validity and consistency. - **Other features**: - Protection or Security measures to prevent unauthorized access. - Active processing to take internal actions on data. - Presentation and Visualization of data. # Database Characteristics - **Self-describing nature of a database system**: - A DBMS **catalog** stores the **description** of the database. - This description is called **meta-data**, which allows the DBMS software to work with different databases. - **Insulation between programs and data**: - Called **program-data independence**, that allows changing data storage structures and operations without having to change the DBMS access programs. # University Database Example - **Mini-world**: are some parts of the real world in which data is stored in a database. - **Mini-world for the example**: is part of the **UNIVERSITY** environment. - **Some mini-world entities**: - STUDENTS - COURSES - SECTIONS (of COURSES) - (academic) DEPARTMENTS - INSTRUCTORS - **Some mini-world relationships**: - **SECTIONS** are of specific **COURSES** - **STUDENTS** take **SECTIONS**. - **COURSES** have prerequisite **COURSES**. - **INSTRUCTORS** teach **SECTIONS**. - **COURSES** are offered by **DEPARTMENTS**. - **STUDENTS** major in **DEPARTMENTS**. # Library Loan Database Example **Figure 3** shows the database structure and sample data for a database that maintains information concerning borrowers, books, loans, and reservations in a library loan system. **Tables:** | Borrower | | | | |---|---|---|---| | BNUM | BNAME | ADDRESS | STATUS | | 30202 | Ahmed Aly | Cairo | g | | 30203 | Aly Fathy | Cairo | plg | | 30204 | Sherif Ahmed | Giza | staff | | Loan | | | | |---|---|---|---| | BOOK# | BNUM | DATE | DUE-BACK | | 0001 | 30202 | 30/10/2005 | | | 0002 | 30202 | 30/10/2005 | | | Book | | | | | | | | |---|---|---|---|---|---|---|---| | BOOK# | TITLE | AUTHOR | PUBLISHER | YEAR | PRICE | SHELF | | 00001 | Database Systems | C.J. Date | XYZ | 2001 | 50 | H1 | | 00002 | Data Models | C.J. Bloggs | ABC | 2000 | 50 | H1 | | 00003 | SOL | C.J. Date | XYZ | 2001 | 40 | H2 | | Reservation | | | |---|---|---| | BOOK# | BNUM | RESERVATION-DATE | | 0001 | 30203 | 30/10/2005 | | 0002 | 30204 | 10/11/2005 |